JP3518072B2 - Negative pressure booster - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a negative pressure type booster which can be automatically operated and is mainly applied to automobiles.

[0002]

2. Description of the Related Art Conventionally, a negative pressure type booster for reducing an operating force during vehicle braking has been widely used. this is,
A constant pressure chamber in which a negative pressure is constantly introduced by communicating with the intake manifold of the engine, a state in which the constant pressure chamber is cut off to communicate with the atmosphere, and a state in which a negative pressure is introduced in communication with the constant pressure chamber are selected. A variable pressure chamber, a vacuum valve that connects and disconnects communication between the constant pressure chamber and the variable pressure chamber, and an air valve that connects and disconnects communication between the variable pressure chamber and the atmosphere, each of which is operated by a brake operation member of a vehicle. By opening and closing the vacuum valve and the air valve,
By setting a differential pressure corresponding to the operating force of the brake operating member between the constant pressure chamber and the variable pressure chamber, a braking force amplified according to the operating force of the brake operating member is generated.

By the way, in recent years, an electrically operated solenoid is provided, and when a certain operating state of the brake operating member is detected, the solenoid opens the air valve to provide a braking force more than the operating force of the brake operating member. There is known a negative pressure type booster that generates a. For example, the present applicant has filed Japanese Patent Application No. 7-15059 prior to the present application.
No. 0 filed an invention relating to the negative pressure type booster described above.

FIG. 4 is a sectional view of the negative pressure type booster described in FIG. 1 of the above application. In this negative pressure type booster, the valve seat 101 provided on the power piston 101 is provided.
a is installed on the input member 102 and the plunger member 10
A sealing member 104 having a sealing function between
Since it is on the side opposite to the output rod 105 in the axial direction, a portion extending from the valve seat 101a of the power piston 101 exists radially outward of the plunger member 103, and This is an obstacle to increasing the seal diameter.

Assuming now that the electromagnetic solenoid 106 is deactivated from the actuated state and the plunger member 103 is returned to the right in FIG. 3 by the spring force of the spring member 107, the spring member 107. The spring force of the plunger member 1
03 and the valve member 108, the plunger member 103 and the valve member 108 are returned against the force generated by the atmospheric pressure. The plunger member 103
And the magnitude of the force generated by the atmospheric pressure acting on the valve member 108 is the air valve diameter formed by the engagement between the valve member 108 and the plunger member 103, minus the seal diameter of the seal member 104. And the value obtained by subtracting the air valve diameter from the effective diameter of the valve member 108. Therefore, in an ideal state, if the seal diameter of the seal member 104, the air valve diameter, and the effective diameter of the valve member 108 are made equal to each other, the spring member 10
7, the electromagnetic force of the electromagnetic solenoid 106 is changed from the non-actuated state to the actuated state, and the plunger member 103 is moved to the spring member 107.
Assuming a case where the electromagnetic solenoid 106 is driven against the spring force, the electromagnetic force of the electromagnetic solenoid 106 can be reduced, and as a result, the electromagnetic solenoid 106 can be downsized.

However, even if this design concept is diverted, in order to secure a passage for the air passing between the air valve portion 108a of the valve member 108 and the air valve seat 103a of the plunger member 103, the air valve is required. A large space 109 is provided between the portion 108a and the vacuum valve portion 108b, and a passage 110 that bypasses the periphery of the plunger member 103 is required to guide the air to the variable pressure chamber. I have no choice.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a negative pressure type booster which has a simple structure and is compact and which can be automatically operated.

[0008]

In order to solve the above-mentioned problems, in the above-mentioned claim 1, a housing and a constant pressure chamber movably installed in the housing and constantly communicating with the negative pressure source in the housing. A movable wall that is separated into a variable pressure chamber that is airtightly separated from the constant pressure chamber, and a movable wall that is connected to the movable wall and projects into the constant pressure chamber, and moves in the axial direction to apply an braking force to the output rod A power piston that outputs toward the output, an input rod that is connected to the brake pedal and is installed in the power piston, and that is movable in the axial direction by a brake operation, and is movable in front of the input rod integrally with the input rod. Linked to
A first input member and a shaft disposed in front of the first input member;
An input member including a second input member movable in a direction ,
By engaging the first input member and the plunger member axially movable by the movement of the first input member, and the air valve valve seat of the plunger member, the variable pressure chamber is removed from the atmosphere. A valve member provided with an air valve portion for shutting off and a vacuum valve portion for shutting off communication between the constant pressure chamber and the variable pressure chamber by engaging with a vacuum valve valve seat of the power piston, and a power source connected to a power source. An electromagnetic solenoid that receives the supply and operates the plunger member, and the vacuum valve valve seat is installed on one side of the first input member and the plunger member and seals between the other side. In the negative pressure type booster located closer to the output rod in the axial direction, the air valve section and the vacuum valve are provided.
The first input member is connected to the first input member by a connecting portion.
Radial protrusions are formed, and the radial protrusions connect the connecting portions.
Beyond was vacuum booster characterized that you have contact with the inner circumference of the power piston.

[0009]

Further, in the above-mentioned claim 2 , the connecting portion has a communication hole communicating with the air valve, and the power piston has an air path connecting the communication hole and the variable pressure chamber. Claims characterized in that
The negative pressure type booster satisfying the condition 1 was adopted.

According to the negative pressure type booster by the means described in claim 1, the vacuum valve valve seat of the power piston is axially arranged on one side of the first input member and the plunger member and on the other side. Since it is located on the output rod side from the seal member with the sealing function between
The diameter of the sealing member can be increased to a value close to the diameter of the air valve. Further, the input member has a radial projection.
Forming the radial projections on the inner circumference of the power piston.
Since it is in contact, even if the input member is tilted, the previous term plan
Does not affect the operation of the jar member.

[0012]

Further, according to the negative pressure type booster by the means described in the second aspect, since the air valve portion and the variable pressure chamber are communicated with each other through the through hole and the air path, the axial direction can be made compact.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Below, only the features of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of a conventional single type negative pressure type booster to which the negative pressure type booster of the present invention is applied, according to a first embodiment of the present invention. Is.

In FIG. 1, a housing 2 of a negative pressure type booster 1 capable of automatic operation is provided with a movable wall 3 whose outer peripheral portion is airtightly fixed and which is movable in the axial direction. The interior of the housing 2 is airtightly separated into a constant pressure chamber 4 and a variable pressure chamber 5 by the movable wall 3. The constant pressure chamber 4 communicates with an intake manifold of a vehicle engine (not shown), which is a negative pressure source, via the inlet 2a, and always generates a negative pressure.

A power piston 6 made of a resin material is inserted into the housing 2 from the rear side thereof, and the movable wall 3 is airtightly fixed to the power piston 6 at its inner peripheral end.

Inside the power piston 6, a first input rod 7 which is a brake operating member of a vehicle (not shown), for example, a brake pedal connected at its right end in FIG. 1 is inserted. 7 is provided with a slit 7a extending in the axial direction, and a connecting pin 8 is inserted movably in the axial direction. The connecting pin 8 is inserted into the through hole 9a provided in the second input rod 9 and the second input rod 9
It is fixed so that it cannot move.

An inner peripheral hole 9b of the second input rod 9 is fitted in an outer peripheral portion 7b of the first input rod 7, and a stepped portion 7c of the first input rod 7 and the second input A locking spring 1 is provided between the rod 9 and the bottom 9c of the inner peripheral hole 9b.
0 intervenes and urges the first input rod 7 and the second input rod 9 in a direction in which they are separated from each other. The second input rod 9 is an input unit 1 of a first input member 11 described later.
It is movably connected to 1a.

A micro switch 12 as a switch means is fixed to the upper portion of the first input rod 7. The micro switch 12 includes an operation unit 12a that emits an electric signal when activated, and a harness 12b that transmits the generated electric signal to the outside. The connection pin 8
A contact member 13 is fixed to the micro switch 1 and
It is possible to contact the second operating part 12a.

The output portion 11b of the first input member 11 fixed to the input portion 11a of the first input member 11 and the second input member 14 abutting on the output portion 11b of the first input member 11 are all It serves to transmit the brake operating force from the second input rod 9 to the reaction disc 15. The output rod 16 connected to the reaction disc 15 receives a brake operating force via the reaction disc 15 and moves to operate a piston of a master cylinder (not shown).

An electromagnetic solenoid 17 is fixed inside, and a first fixing member 18 made of an iron core material.
a is hermetically fixed to the power piston 6 via a seal member 19. The second fixing member 18b, which is also made of an iron core material, is fitted and fixed to the first fixing member 18a.

The electromagnetic solenoid 17 is connected to a power source of a vehicle (not shown) by an electric wire 17a, and an electromagnetic force can be generated by supplying electric power from the power source through the electric wire 17a.

The plunger 20 has a first plunger portion 20a and a second plunger portion 20 for reasons of assembling.
b and are fixed to each other. The plunger 20 is engaged with the input portion 11a of the first input member 11 via the seal member 21 in the inner peripheral portion of the second plunger portion 20b in a hermetically and relatively movable manner. .

The hook portion 2 installed at the ends of the input portion 11a of the first input member 11 and the second plunger portion 20b.
An urging spring 22 is interposed between 0ba and 0ba in a compressed state. Further, a flange portion 11ba is installed on the output portion 11b of the first input member 11 and engages with a shoulder portion 20aa installed on the first plunger portion 20a.

Therefore, when the second input rod 9 is in the non-actuated state, the plunger 20 receives the urging force in the right direction in FIG. 1 by the urging spring 22 and the first plunger. The portion 20a is stationary by engaging with the flange portion 11ba.

A spring retainer 24 for receiving a return spring 23 is fixed to the connecting pin 8. A first retainer 25a forming a valve member 25 is fixed to the power piston 6 via the spring retainer 24 and a return spring 23 while receiving an elastic force from the second input rod 9. The seal member 25b engages with the first retainer 25a on the outer circumference thereof, and has a sealing function between the seal member 25b and the spring retainer 25c on the inner circumference thereof, and further, the first retainer 25a and the spring retainer 25c. A valve spring 25d is interposed between the two. The spring retainer 2
A valve plate 25e extending to the output rod 16 side is further fixed to 5c, and the spring retainer 25
An air valve member 25f and a vacuum valve member 25g are integrally molded and fixed to c and the valve plate 25e, respectively. The valve plate 25e is fitted with a sealing member 25h that produces a sealing function with the power piston 6.

The input portion 11a of the first input member 11 is provided with a radial projection 11aa, which can slide on the inner peripheral surface of the power piston 6 through the second plunger portion 20b and the valve plate 25e. Is in contact with.

By adopting the above structure, the air valve member 25f is engaged with the second plunger portion 20b when the second input rod 9 is in the inoperative state. Further, when the second input rod 9 is in the operating state,
The vacuum valve member 25g can be engaged with a valve seat 6a provided on the power piston 6. A key 26 is provided in the key groove 6b installed in the power piston 6.
Is inserted into the housing 2 via the damper member 27.
Is in contact with.

Further, the valve plate 25e is provided with a through hole 25i communicating with the air valve member 25f, and the power piston 6 is provided with the through hole 25i.
An air path 6c is provided to connect the variable pressure chamber 5 with the variable pressure chamber 5, and an axial space from the air valve member 25f to the variable pressure chamber 5 is not required.

The operation of the negative pressure type booster 1 will be described below. When the driver is not operating the brake operating member (not shown) of the vehicle, the negative pressure booster 1 is in the state shown in FIG. 1, the air valve member 25f is in the engaged state with the second plunger portion 20b, and Since the vacuum valve member 25g is disengaged from the valve seat 6a of the power piston 6, the variable pressure chamber 5 is a negative pressure source via the constant pressure chamber 4 and an intake manifold of a vehicle engine (not shown). Is in communication with.

When a driver operates a brake operating member of the vehicle, for example, a brake pedal, the first input rod 7 connected to the brake operating member receives a brake operating force to move leftward in FIG. , Overcoming a predetermined biasing force of the locking spring 10 to fill the gap originally set between the first input rod 7 and the second input rod 9 and then to the first input rod 7. The second input rod 9 moves integrally. Therefore, the second
The first input member 11 fixed to the input rod 9 is also the first
The input rod 7 and the second input rod 9 move integrally to the left in FIG. 1, where the operation of the first input rod 7 causes the first input rod 7 and the second input rod 9 to move. When the gap between the
The micro switch 12 fixed to the input rod 7 is the contact member 1 fixed to the second input rod 9.
By moving in three directions, the contact portion 13 is attached to the operating portion 12a.
Contacting each other, and eventually the contacting part 13 moves the operating part 12
By pressing a, the micro switch 12 is operated, and the micro switch 12 emits an electric signal.

By the movement of the first input member 11, the plunger 20 is also moved to the left in FIG. 1 via the flange portion 11ba of the first input member 11, so that the air valve member 25f and the vacuum. The valve member 25g also moves leftward in FIG. 1 together with the plunger 20 due to the urging force of the valve spring 25d, and eventually the vacuum valve member 25g.
Comes into contact with the valve seat 6a of the power piston 6, and the variable pressure chamber 5 is cut off from the constant pressure chamber 4, so that the communication with the negative pressure source of the vehicle is also cut off.

Further, when the plunger 20 moves to the left in FIG. 1, the engagement between the air valve member 25f and the plunger 20 is released, and the variable pressure chamber 5 is released.
Communicate with the atmosphere. Therefore, an atmospheric pressure difference is generated between the constant pressure chamber 4 and the variable pressure chamber 5 due to the inflow of air into the variable pressure chamber 5, so that the movable wall 3 and the power piston connected thereto, which receives a load due to the atmospheric pressure difference. 6 outputs the amplified braking force to the output rod 16 via the reaction disc 15. After that, the reaction force applied to the second input rod 9 and the first input rod 7 from the reaction disc 15 via the second input member 14 and the first input member 11 causes the air valve member 25f to move. The plunger 20 or the vacuum valve member 25g and the valve seat 6a of the power piston 6 are selectively engaged with each other, depending on the driver's brake actuation force applied to the first input rod 7. The assisting force of the negative pressure type booster 1 is controlled.

For example, an obstacle appears in front of the vehicle, and the microcomputer of the vehicle (not shown), for example, based on a pedal stroke value detected by a pedal stroke switch (not shown) attached to the brake pedal, the brake pedal has a certain threshold value. A method for determining that emergency braking is required when it is detected that the pedal has been operated at the above pedal stroke speed, or an image is processed by a CCD camera, or an obstacle exists in front of the vehicle by a distance measuring sensor. Is detected, and at that time, the first input rod 7 is operated with a braking force equal to or more than a set value, and it is detected that the micro switch 12 is operating the brake pedal, an emergency brake is required. Determined the need for emergency braking by the method of determining that there is Supplies power to the electromagnetic solenoid 17 via a wire 17a from the power supply, apart from the driver's brake operation. The electromagnetic solenoid 17 supplied with electric power generates an electromagnetic force to resist the frictional resistance of the plunger 20 with the seal member 21 and the urging force of the urging spring 22, and the first input member. 1
It is moved to the left in FIG. 1 regardless of the operation of 1.
As described above, the movement of the plunger 20 causes the air valve member 25f and the vacuum valve member 25g to move leftward in FIG. 1 together with the plunger 20 by the urging force of the valve spring 25d. The vacuum valve member 25g and the valve seat 6a of the power piston 6 are engaged with each other, and the engagement of the air valve member 25f and the plunger 20 is released. Therefore, the variable pressure chamber 5 is disconnected from the negative pressure source of the vehicle and communicates with the atmosphere, and when the atmospheric pressure flows into the variable pressure chamber 5, the power piston 6 outputs a braking force to the output rod 16, The brake pressure is generated in the master cylinder by operating the piston of the master cylinder.

The reaction force generated by the braking force of the power piston 6 and the braking force generated by the operation of the brake pedal and transmitted to the second input member 14 are applied to both sides of the reaction disc 15. Balance.

When the driver of the vehicle judges that the brake operation is no longer necessary and the brake pedal of the vehicle is released, the plunger 20 is integrated with the first input member 11 by the retraction of the second input rod 9. And moves to the right, and the air valve member 25f moves to the second plunger 2
0b, the vacuum valve member 25g is separated from the valve seat 6a of the power piston 6, so that the variable pressure chamber 5 is cut off from the atmosphere and communicates with the constant pressure chamber 4.
Since the positive pressure inside the variable pressure chamber 5 decreases, the assisting force to the power piston 6 also decreases.

When the brake operating force applied to the first input rod 7 decreases and becomes less than the set load of the locking spring 10, the urging force of the locking spring 10 causes the first input rod 7 to move. And the second input rod 9
Are separated from each other, the contact of the contact portion 13 with the operating portion 12a of the micro switch 12 is released, and the electric signal generated by the micro switch 12 disappears. When a microcomputer (not shown) detects that the electric signal of the micro switch 12 has been released, the electromagnetic solenoid 17 is no longer connected to the plunger 20 because the power supply to the electromagnetic solenoid 17 is stopped. 1, the plunger 20 is returned to the right side in FIG. 1 by the urging force of the urging spring 22. Plunger 2
1 moves to the right in FIG. 1, the air valve member 25f also engages with the plunger 20,
And is returned to the right at the vacuum valve member 25.
g is disengaged with the valve seat 6a of the power piston 6. Therefore, the variable pressure chamber 5 is disconnected from the atmosphere, communicates with the negative pressure source of the vehicle, and the pressure difference between the constant pressure chamber 4 and the variable pressure chamber 5 is reduced to bring the variable pressure chamber 5 into a state along the normal brake. After that, the input is reduced to return to the initial state.

As in the above-described embodiment, the vacuum valve member 25g has the valve plate 25e.
Since it is positioned closer to the output rod 16 side than the seal member 21, it is possible to eliminate the obstacle that increases the diameter of the seal member 21, and the seal diameter is set to the air valve member 25f and the first. It is possible to bring the retainer 25a close to the seal diameter of the seal member 25b. In the above-described embodiment, since the sealing function is generated in the inner diameter portion of the seal member 25b, the seal diameter of the seal member 25b is reduced, and the seal diameter of the seal member 21 is changed to the first retainer 25a. The seal diameter of the seal member 25b can be easily approached.

FIG. 2 is a sectional view of a negative pressure type booster according to a second embodiment of the present invention. In the figure, the difference from the first embodiment is that the seal member 25b is attached to the spring retainer 25c and a sealing function is generated at the outer periphery thereof.

In the above embodiment, the plunger is moved to the master cylinder side by the electromagnetic solenoid, but the present invention is not limited to this, and the plunger is on the brake pedal side of the vehicle. It is also applicable to those driven by.

According to the automatically actuable negative pressure type booster of the present invention, the vacuum valve member 25g is positioned closer to the output rod 16 than the seal member 21 by the valve plate 25e.
1 can be eliminated, and the seal diameter can be brought close to the seal diameters of the air valve member 25f and the seal member 25b of the first retainer 25a. Therefore, the electromagnetic solenoid 17
Can be reduced, and the size of the electromagnetic solenoid 17 can be reduced.

Further, the valve plate 25e is provided with a through hole 25i communicating with the air valve member 25f, and the power piston 6 is provided with a through hole 25i and a variable pressure chamber 5.
Since the air path 6c that communicates with and is provided, there is no need for an axial space from the air valve member 25f to the variable pressure chamber 5, and the responsiveness can be improved.

FIG. 3 shows a third embodiment of the negative pressure type booster according to the present invention.
Represents an embodiment of. This embodiment is different from the first embodiment in that the air valve member 25f and the seal member 25 are
That is, b is integrated to form the control valve 26.

[0045]

As described above, according to the present invention, a compact negative pressure type booster capable of automatic operation can be provided, and thus a low cost negative pressure type booster can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a negative pressure type booster according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a negative pressure type booster according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a negative pressure type booster according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a negative pressure type booster according to the prior art.

[Explanation of symbols]

1 Negative Pressure Booster 2 Housing 3 Movable Wall 4 Constant Pressure Chamber 5 Variable Pressure Chamber 6 Power Piston 6a Valve Seat 6c Air Path 11 First Input Member 11aa Radial Protrusion 17
Electromagnetic solenoid 20 Plunger 21 Seal member 25 Valve member 25e Valve plate 25f Air valve member 25g Vacuum valve member 25i Through hole

Claims (2)

(57) [Claims] 1. A housing, a constant pressure chamber that is movably installed in the housing and is in continuous communication with a negative pressure source in the housing, and a variable pressure chamber that is hermetically separated from the constant pressure chamber. A movable wall that separates, a power piston that is coupled to the movable wall and projects into the constant pressure chamber, and outputs a braking force toward an output rod by moving in the axial direction, and the power piston that is coupled to a brake pedal An input rod that is installed inside and is axially movable by a brake operation; and a first input member that is connected to the input rod so as to be movable integrally with the input rod in front of the input rod.
And is arranged in front of the first input member and is movable in the axial direction.
An input member consisting of a capacity of the second input member, the first input member engages and, a plunger member movable in the axial direction by the movement of the first input member, an air valve valve of the plunger member An air valve portion that shuts off the variable pressure chamber from the atmosphere by engaging with a seat and a vacuum valve portion that shuts off the communication between the constant pressure chamber and the variable pressure chamber by engaging the vacuum valve valve seat of the power piston. A valve member provided with the electromagnetic valve, an electromagnetic solenoid connected to an electric power source and actuating the plunger member by receiving supply of electric power,
In the vacuum booster which is located on the output rod side in the axial direction than the sealing member for sealing between the installed the other side to one side of the plunger member and the first input member,
The air valve portion and the vacuum valve portion are connected to each other.
And the first input member has a radial protrusion.
Formed, the radial protrusion extends beyond the connecting portion and
Vacuum booster according to claim Rukoto the inner periphery of word piston not abut. 2. The connecting portion communicates with the air valve portion.
The power piston is provided with a communication hole.
The negative pressure type booster according to claim 1, further comprising an air path connecting the communication hole and the variable pressure chamber .